Masanobu Shiga
Kyushu University
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Featured researches published by Masanobu Shiga.
Journal of Microbiological Methods | 2012
Tadayuki Tsukatani; Hikaru Suenaga; Masanobu Shiga; Katsuya Noguchi; Munetaka Ishiyama; Takatoshi Ezoe; Kiyoshi Matsumoto
The minimum inhibitory concentrations (MICs) obtained from the susceptibility testing of various bacteria to antibiotics were determined by a colorimetric microbial viability assay based on reduction of a tetrazolium salt {2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt (WST-8)} via 2-methyl-1,4-napthoquinone as an electron mediator and compared with those obtained by the broth microdilution methods approved by the Clinical and Laboratory Standard Institute (CLSI). Especially for drug-resistant bacteria, the CLSI method at an incubation time of 24h tended to give lower MICs. The extension of incubation time was necessary to obtain consistent MICs for drug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococi (VRE) and multi-drug resistant Pseudomonas aeruginosa (MDRP) in the broth microdilution method. There was excellent agreement between the MICs determined after 24h using the WST-8 colorimetric method and those obtained after 48-96 h using the broth microdilution method. The results suggest that the WST-8 colorimetric assay is a useful method for rapid determination of consistent MICs for drug-resistant bacteria.
Analytical Communications | 1998
Makoto Mizoguchi; Munetaka Ishiyama; Masanobu Shiga
A newly synthesized water-soluble phenylenediamine derivative, N-methyl-N-phenyl-3-sulfophenylenediamine sodium salt, proved to be of value as a reagent for the colorimetric determination of hydrogen peroxide in clinical analyses. The compound reacted with Trinder’s reagents to give chromogens with a higher sensitivity, a longer wavelength (>750 nm) as well as a higher water solubility compared with a commonly used reagent.
Cytotechnology | 1995
Kazuhiko Nagira; Midori Hayashida; Masanobu Shiga; Kazumi Sasamoto; Kenyu Kina; Kazuhiro Osada; Takuya Sugahara; Hiroki Murakami
Human-human hybridoma cells secreting a human monoclonal antibody were cultured in a serum-free medium containing various organic pH buffers in order to clarify their effects on cell growth and antibody production. Organic pH buffers having either one sulfonic acid and several acyclic amine moieties, or several cyclic amine moieties containing two amino nitrogen did not inhibit cell growth; while other organic buffers sulfonic acid moiety plus several cyclic amine moieties containing one amino nitrogen slightly decreased cell growth, but enhanced antibody production. Using Fujitas organic conceptual diagram, a relationship between the organicity and inorganicity of a pH buffer to cell growth and antibody production was found. pH buffers with large inorganicity and small organicity values were favorable for cell growth, and buffers with small inorganicity and large organicity values were preferred to enhance antibody production. Although the pH buffering range affects cell growth, its effect on antibody production is not clear. In conclusion, 2-morpholinoethanesulfonic acid (MES), 3-morpholino-propanesulfonic acid (MOPS) and 1, 2-N, N′-bis[N″, N‴-di(2-sulfonoethyl)piperazinyl]ethane (Bis-PIPES) are shown to be the most optimal of the buffers tested, because they enhanced antibody production without decreasing the cell growth among the pH buffers tested here.
18th International Conference on Strongly Correlated Electron Systems, SCES 2016 | 2017
Masanobu Shiga; Naoto Nishimura; Yuji Inagaki; Tatsuya Kawae; H. Kambara; Kenichi Tenya
Using the point-contact Andreev reflection (PCAR) technique, we have performed spin polarization measurements in a polycrystalline SrRuO3 to study the difference of the spin polarization between the ballistic and diffusive transport samples. PCAR spectra were measured with Nb tips for T = 4.2 K with changing the contact area mechanically. The results were well fitted by the modified Blonder-Tinkham-Klapwijk (mBTK) model. We estimate the spin polarization P ≈ 0.59, which is slightly larger than that of a single crystal film with P ≈ 0.51 due to the change of transport property.
28th International Conference on Low Temperature Physics, LT 2018 | 2018
Hiroki Takata; K. Ienaga; Masanobu Shiga; S. Islam; Yuji Inagaki; Hiroyuki Tsujii; K. Hashizume; Tatsuya Kawae
We report experimental study on low-temperature hydrogen (H) absorption in vanadium (V) and niobium (Nb) nanocontacts below T = 20 K using a point-contact spectroscopy (PCS) technique. When a small bias voltage is applied between both sides of nanocontacts immersed in liquid H2, the differential conductance (dI/dV) and the second derivative (d2 I/dV 2) are changed from those for pure V and Nb nanocontacts. Further, the spectra approach to those for a high concentrated phase of H with increasing the bias voltage. The results indicate that in-situ investigation of H absorption process from liquid H2 is possible through dI/dV and d2 I/dV 2 measurements using the PCS technique.
Biological & Pharmaceutical Bulletin | 1996
Munetaka Ishiyama; Hideyuki Tominaga; Masanobu Shiga; Kazumi Sasamoto; Yosuke Ohkura; Keiyu Ueno
Chemical & Pharmaceutical Bulletin | 1993
Munetaka Ishiyama; Masanobu Shiga; Kazumi Sasamoto; Makoto Mizoguchi; Pin-gang He
Chemistry Letters | 1980
Masanobu Shiga; Makoto Takagi; Keihei Ueno
Bulletin of the Chemical Society of Japan | 1984
Masanobu Shiga; Hiroshi Nakamura; Makoto Takagi; Keihei Ueno
Archive | 1997
Munetaka Ishiyama; Yoko Miyazono; Masanobu Shiga; Kazumi Sasamoto